Method of forming sand molds.



No. 697,383.l

`S. J, ADAMS.

METHDD 0F FOBMING SAND HOLDS.

(Application filed Feb. 6, 1901.)

Patented Apr. 8, |902.

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UNITED STATES PATENT OFFICE.

STEPHEN JARVIS ADAMS, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO MARCELLIN C. ADAMS, OF PITTSBURG, PENNSYLVANIA.`

IVIETHODSOF FORMING SAND MOLDS.

SPECIFICATION forming part of Letters Patent N o. 697,388, dated April 8, 1902.

Original application filed March 30, 1897, Serial No. 629,919. Divided and this application filed February 6, 1901. Serial No. 46,162. (No model.)

To all whom if may concern.'

Be it known that I, STEPHEN JAEvls ADAT/is, a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Forming` Sand Molds; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to a method of formio ing sand molds, and more particularly to the method which is known as the jarring proeess, wherein the sand is placed around the patterns in the fiask, a surplus of sand being held in a reservoir above the flask and the i 5 whole mass being raised and then permitted to drop or descend quickly and strike a stationary block, and thereby impart a jarring to the sand within the flask', a sufficient number of these jars being imparted thereto to o compact the sand.

The present application is a division of my application filed March 30, 1897, Serial No. 629,919, and the invention herein claimed is designed to overcome certain difficulties existing in the methods of forming sand molds according to this system as heretofore praeticed.

In the jarring process of forming sand molds as heretofore practiced the reservoir, which 3o rested upon the top of the flask, consisted of a shallow frame open at both ends, which reservoir was filled with sand, which by the jarring operation passed down either entirely or mostly into the flask. I have discovered that the jarring stroke causes a rebound in this shallow body of sand within the reservoir and in the upper part of the flask and that while the sand :is packed evenly and solidly around the lower portions of the pattern in the fiask 4o by reason of this rebound it is insufliciently packed in the'upper part ofthe ask, so that the sand in the upper part of the fiask is loose and spongy, thereby causing the formation of swells on the casting. In case the jarring operation is continued under thisold process with the shallow body of sand above the fiask in order to compact the sand more firmly in theupper portion of the flask the said upper portion becomes cracked and filled with crev- 5o lees, thereby rendering it wholly impracticable. It has therefore been'found necessary. in such jarring process to compact the sand in the upper portion of the flask by means of a hand-tool after the jarring operation is completed. This, however, is open to the defect that it forms a crust or solid layer of sand in the upper portion of the fiask,which prevents the escape of gases and steam, which are always present in the casting operation, due probably to the organic matter existing in the 6o sand or to other causes. As a consequence it has been found necessary to puncture or perforate the mold by means of a prod or wire in order to permit the escape of gases and steam.

The object of the present invention is to overcome these defects in the old method of forming sand molds according to this system and to provide a method of forming such molds which insures the even packing of the sand in the mold throughout its height, thereby 7o forming a mold which is more perfect than under the old process, which will not result in the formation of swells in the casting, and in which the sand is homogeneous throughout, so that the sand in the upper portion thereof while it is compacted is still porous enough to permit an escape of steam and gases from the mold. This object I accomplish by the employment of a superincumbent column of sand above the flask of sufficient height to 8o provide a body of, .sand having sufficient weight to prevent the rebound of the sand within the flask, so that the sand in the upper portion of the flask will be packed as firmly as the sand in the lower portion of the fiask, thereby forming a mold which will not produce swells on the casting and which has the sand in the upper portion thereof rm, but porous, so that the gases or steam can readily escape. 9o

To enable others skilled in the art to practice my invention, I will describe a suitable form of apparatus for carrying the same in effect, such apparatus being illustrated in the accompanying drawings, in which- Figure 1 is a side elevation of such apparatus partially broken away. Fig. 2 is a crosssection of the same on the line 2 2, Fig. 1; and Fig. 3 is a perspective view`of the fiaskand the base of the sand-feeding chute, illustratroo ing the cutting and sleeking of the mold, said view being partially broken away.

The apparatus illustrated comprises the framework A,which rises from the bed or floor b, which also supports the jarring-block b, said framework being composed of upright standards a and any suitable cross-beams a a?. The apparatus has also the jarring-table c and the sand-feeding chute d, which is, at least during the jarring operation, supported on said table independently of the iiask, being preferably permanently supported on the table. The upright standards a carry suitable guides or guideways, which, as shown, are placed a sufficient distance apart to insure t the absolutely-vertical movement of the jarring-table and sand-feeding chute. As illustrated, there are the lower guideways e, which are engaged by guides c on the jarring-table c, and the upper guideways f, engaged by guides f near the upper end of the chute d. As it is desirable to protect the guides and guideways from contact with the sand, which is liable to cut and wear into the same, I prefer to extend theguides c' upwardly from the jarring-table c to a point above the base of the chute (l, so that there will be no liability of the sand entering between the guides and guideways. The sand-feeding chute is supported some distance above the jarring-table on suitable legs cZ/ d2, the legs d being placed two on each side near to the front and back faces of the chute, while the legs (Z2 are placed about midway and provide bearings for the cams g, which act to clamp upon the jarringtable the flask h, in which the mold is made, the iiask 7L having lugs 7L in line with said cams g, so that after the flask is inserted under the sand-feeding chute the cams may be thrown down by means of the handles g and force the fiask against the jarring-table and hold it firmly during the jarring operation. Suitable rests or supports for the handles g when the cams are not in use may be provided upon the legs d2. It will be noticed that between the fiask 7L and chute (Z a slight space isleft, as at h2, this space being provided for the passage of the cutting and sleeking meehanism referred to hereinafter.

The sand-feeding chute is made with a slight upward taper, increasing gradually in diameter from the top tothe bottom, so as to prevent the sand from sticking therein. It is preferable to make this chute from eight to ten feet in height, so that it will hold a large body of sand and so that the sand in the lower part thereof will be sufficiently packed in any ordinary diameter of chute to maintain the weight of the sand above without dropping out. Its principal function is to resist any tendency to rebound of the sand within the liask, providing in this waya body of sand which can only be caused to move by the jars imparted to the chute and which will remain therein when the liask is withdrawn from under the chute and before it is again placed thereunder for the making of the next mold. If any difficulty is experienced in the holding of the sand in the chute, it can be overcome by the employment of a few wires d3, extending across the base thereof; but this is only necessary in forming molds of considerable width. The supply of sand may be maintained within the sand-feeding chute in any suitable way, being fed thereto by proper mechanism.

In order to raise and lower the jarring-table and its sand-feeding chute, I may employ any suitable verticallymoving mechanism operating in any suitable way, the preferable way being bysteam or air pressure operating Within an engine K, having a cylinder 7;, which operates through the piston 7c a piston-rod 7a2, from which the sand-feeding chute (l is suspended by a flexible support Z, which is preferably formed of a wire rope, the advantage of this construction being that the power to lift the table and chute being applied through a fiexible connection permits the same to move as guided from the frame, and therefore permits it to move in an exactly vertical course in dropping, the lifting mechanism having no control whatever upon the dropping of the table and its chute. In order to give a direct upward pull of the wire rope l to the chute, it is passed first around a pulley 7c3 on the lower end of thepiston-rod 7a2 and thence passes around the pulleys Z', supported on the cross-beam a', and in such position that the rope then passes in a true vertical course down to the loops Z2, by which it is connected on each side to the sandfeeding chute d. The admission and escape of air or steam to the cylinder 7c of the lifting-engine is controlled by any suitable valve mechanism operating through the valve-chest m, the valve-rod m being under any suitable control. The construction of the engine will of course require a rapid escape of the air to permit the jarring stroke; but this can be obtained by the use of a cylinder somewhat lon'ger than the stroke, which will at the same time permit the piston to cushion before reaching the lower end of the cylinder, while the stroke of the piston and its rod may be controlled by a suitable stop n, the pistonrod extending up through the upper cross beam a2, to which the cylinder 7c is connected, and having a head or enlargement n', which engages with said stop n, a suitable spring or other cushion u2 being interposed between the same, as found necessary. The stroke of the apparatus-that is, the lift of the table and it-s chute above the jarring-block bof course depends upon the mold being made and the particular stroke necessary for the packing of the sand. Ou an average a lift of about one foot will be sufficient, and the cylinder and valve mechanism can of course be made of proper construction to give such stroke, permittinga :free d rop and the cushioning of the piston.

It will of course be understood that the sand is packed solidly in the lower part of the feed- IOO IZO

ing-chute and the upper part of the flask and that before the finished mold can be withfeeding chute d, the space varying in different mechanisms, but being generally about one-half an inch in width. To cut off the sand, I employ a cutting and sleeking frame p, which, as shown in the drawings, is formed Y of a light frame, having two arms p' extending forward and carrying at the front end a wire p2, stretched taut between said arms, the arms being of a thickness such as to pass easily through the space h2 between the flask and chute, so that when this frame is pushed horizontally through said space the thin wire cutter will cut through the sand, and so form a division thereof, separating the sand within the flask from that within the chute. As the wire cutter forms a rough surface upon the sand, in order to sleekth'e sand within the flask and also to aid in packing the sand at the base of the feeding-chute I employ back ofthe sand-cutter the sand-sleeker p3, which, as shown, is formed of Ia slat corresponding inthickness to the frame p and tapering gradually to an edge on one or both sides, as at p4, so that as the wire cuts through` the sand this sleeker will follow it and smooth over the surface of the sand both above and below it, preferably having this action bothv in the entering and withdrawing stroke of the frame, and so smoothing the surface of the'finished mold and packing the sand up into the chute d, which will increase the binding force of the sand at the ybase thereof and so aid the same in holding the sand above it within the chute. 1

When the apparatus above described is einployedin'the making of molds, I generally proceedas follows: The'sand for filling the flask may either all be drawn from the'sandfeeding chute or a certain portion of mealy sand-such as will conform more perfectly toy the pattern 7', which extendsup from the pattern plate i" into the flask h-may first be filled around said patterns before the pattern-plate and flask are placed` in posit-ion under the sand-feeding chute, such feeding of mealy sand being accomplished `by hand or in any suitable way. The pattern-plate, with the flask resting thereon, i'splaced on the jarring-table c under the sand-feeding chute and is clamped in place'by the cams g.r The apparatus is then ready for the making of the mold, and throughfthe movementof the valve mechanism controlling the liftingengine K the jarring-table and its sand-feeding chute are raised and dropped, so that the jarring-table c strikes the jarring-block b and imparts thejar to the same, the action offwhich is to jar the sand from the sandfeeding chute down into the flask, either filling the flask entirely through said chute when the empty ask, with its patterns, is

placed under the same or filling the'portion of the flask unfilled withsand. In so doing the sand from the chute acts as a `weight upon the sand in the flask andA prevents the rebund of the sand from the jar in the upper part of the flask, which has been the serious defect in the prior methods employed in this system of molding, so that the entire effect of the jar in packing the sand within the flask is obtained, the whole body of sand within the long feeding-chute moving down at each jar and holding the sand to the position to which it is brought by the jar without permitting any rebound thereof, the only rebound being in the sand in the upper part of the sand-feeding chute, where it can have no effect whatever upon the sand packed within the flask. Any suitable number of jars may grasps the cutting and sleeking frame p and pushes it through the space between the flask and chute andthe wire p2 cuts through the sand, while the sleeker 193, following the wire, smooths the surface of the sandboth of the'mold and at the bottom of the chute, so

finishing the top surface ofthe mold and aid-` ing in packing iof the sand at ithe base of the chute, which will increaselthe holdthereof and assist it in.` holding the mass of sand above it. v withdrawn and the ask drawn out horizontally and the patternswithdrawn and any necessary cores inserted inthe mold,thus cornpletingit.,v A new flask may then` be placed upon the pattern-plate andthe operation repeated. The sandwithin the feedingchute can ybe maintained at the proper height1 by means of any suitable feeding mechanism.

It will be seen that by the method described the entire body of sand within` the Iflask is packedl to a uniform density, so thatA every portionof the mold-walls offer an equal resistance to the molten metal in the mold, and` said mold is of equal porosity at all points,

4sothat' gas and steam can readily escape therefrom. t y What'I claim as myinvention, .to secure by Letters Patent, is-A and desire IOO The clamping-cams g: arev then 4 IIO IIS

The herein-described method Vof forming v sand molds, consisting in impartingajar to a flask containing sand around the pattern and to a superincumbent body of sand of sufficient height to act as a weight andfprevent rebound of the sand in the upper, part of the flask inythejarring action.

In testimony whereof I, the said STEPHEN eI. ADAMS, have hereunto setmy hand.

STEPHEN JARVIS ADAMS.

Witnesses:

ROBERT C. ToTTEN, F. W. WINTER. 

